Wildfires lead to decreased carbon and increased nitrogen concentrations in upland arctic streams.

The Central Siberian Plateau is undergoing rapid climate change that has resulted in increased frequency of forest fires and subsequent alteration of watershed carbon and nutrient dynamics. Across a watershed chronosequence (3 to >100 years since wildfire) we quantified the effects of fire on quantity and composition of dissolved organic matter (DOM), stream water nutrient concentrations, as well as in-stream nutrient uptake. Wildfires increased concentrations of nitrate for a decade, while decreasing concentrations of dissolved organic carbon and nitrogen (DOC and DON) and aliphatic DOM contribution for five decades. These post-wildfire changes in stream DOM result in lower uptake efficiency of in-stream nitrate in recently burned watersheds. Nitrate uptake (as uptake velocity) is strongly dependent on DOM composition (e.g. polyphenolics), ambient dissolved inorganic nitrogen (DIN), and DOC to DIN ratios. Our observations and experiments suggest that a decade-long pulse of inorganic nitrogen and a reduction of DOC export occur following wildfires in streams draining the Central Siberian Plateau. Increased fire frequency in the region is thus likely to both decrease DOM and increase nitrate delivery to the main stem Yenisei River, and ultimately the Arctic Ocean, in the coming decades.

[Endovascular repair of abdominal aortic aneurysm in a patient with transplanted kidney]. / Éndoprotezirovanie anevrizmy briushnoi aorty u bol'nogo s transplantirovannoi pochkoi.

Endovascular repair of the abdominal aorta is a method of choice in pronounced concomitant pathology and high risk of open surgical treatment. The article deals with a clinical case report of successful surgical management of a patient with an infrarenal aortic aneurysm, transplanted kidney, chronic renal insufficiency, secondary diabetes mellitus, multifocal atherosclerosis with predominant involvement of coronary arteries and lower-limb arteries, in whom open surgical treatment was associated with high risk. Endoprosthetic repair of the abdominal aortic aneurysm was performed with a good postoperative outcome.

[Endovascular prosthetic repair of abdominal aortic aneurysm combined with crossover femorofemoral bypass grafting].

In pronounced concomitant pathology and high risks of open operative treatment endovascular prosthetic repair of the abdominal aorta is a method of choice. Presented herein is a clinical case report concerning successful surgical treatment of a patient with an aneurysm of the infrarenal portion of the aorta and high risk of open operative treatment. The patient underwent unilateral endovascular prosthetic repair of the abdominal aortic aneurysm and crossover femoro-femoral bypass grafting with a good postoperative outcome.

[Own experience endovascular prosthetic repair of abdominal aortic aneurysms].

Endovascular prosthetic repair has increasingly been used over the last several decades. This type of intervention is indicated for patients running a high surgical and anaesthesiological risk of an open surgical procedure. The experience gained in endovascular prosthetic repair of abdominal aortic aneurysms makes it possible to extend the indications for its practical application. The authors describe herein their experience gained in a total of 20 procedures of endovascular prosthetic repair of abdominal aortic aneurysms using the Gore Excluder endograft device in patients running a high risk of an open surgical intervention. There were neither short -nor long-term lethal outcomes. Three patients after endovascular prosthetic repair were found to have type 1 endoleak and two appeared to have type 2 endoleak. Type 1 endoleaks were coped with intraoperationally. Dynamic follow-up (at 1, 6, 12 months after surgery) of patients including computed tomography showed no complications whatsoever (i. e., no endoleaks, endograft migration, nor increase in the aneurysm's diameter). After endografting of abdominal aortic aneurysms there were neither cardiac nor respiratory complications in the immediate postoperative period. Hence, endografting of an abdominal aortic aneurysm is a method of choice for high-risk patients.

Comparative analysis of carotid endarterectomy late outcomes related to intervention modality.

The paper presents a comparative analysis of late outcomes after 105 carotid endarterectomies (CEA) performed in 89 patients from 1997 to 2003, including 95 patients (90.5%) operated for atherosclerotic stenosis of internal carotid artery (ICA) and 7 patients (6.6%)--for combined ICA stenosis and tortuosity. The severity distribution of cerebrovascular insufficiency (CVI) was the following: grade I--in 22.8%, grade II--in 12.4%, grade III--in 25.7% and grade IV--in 38.1% of patients. CEA methods included eversion endarterectomy in 50.4% cases and open (classic) surgical CEA with PTFE patch angioplasty in 49.6% cases. Mean follow-up period was 31.8 months for the eversion CEA group and 37 months--for the open CEA group (from 3 to 72 months). In 76.4% patients the duration of follow-up period exceeded 1 year. During the follow-up period all patients underwent clinical examination and color duplex scanning of reconstructed CA segment with assessment of diameter, vascular wall thickness and blood flow. TIA was registered in 1 patient from eversion CEA group and in 1 patient from open CEA group. Thus, in the long-term postoperative period 98% of patients were free from neurological complications. Hemodynamically significant restenoses developed in 8 cases (7.6%), including 4 patients from the eversion CEA group and 4 patients from the open CEA group. Myointimal hyperplasia (> 3 mm) accompanied by hemodynamical alterations occurred in 1 patient from the eversion CEA group and in 2 from the open CEA group. In the rest of cases restenoses were related to atherosclerotic plaque formation. In conclusion, the long-term outcomes indicate that CEA is effective in the prevention of cerebrovascular events regardless of carotid angioplasty strategy. The rate of late postoperative restenoses was similar for eversion and open CEAs. Both modalities can be promising for the surgical correction of CA stenoses.

Carotid thromboses in the early postoperative period after carotid endarterectomy.

The paper analyzes 10 cases of internal carotid artery (ICA) thrombosis, which occurred after 635 carotid endarterectomies (CEA), carried out from January 1997 to July 2004. CEA procedures included 346 (54.5%) open CEAs with PTFE patch angioplasty and 289 (45.5%) eversion CEAs. Patients with thromboses in the reconstructed area (n=10) had the profiles of comorbidities and cerebrovascular insufficiency grade similar to the total CEA group (p>0.1). Differences concerned the higher rate of atrial fibrillation cases (10%), diabetes mellitus (30%) and contralateral ICA occlusions (20%) in the group of thromboses (p>0.1). Among these 10 patients, 5 underwent eversion CEA (1.44% of the total eversion CEA group) and 5 - open CEA with patch angioplasty (1.73%). In 8 patients thromboses manifested as local neurological symptoms in the area supplied by the operated carotid artery. One patient demonstrated the progression of general cerebral symptomatology, while in the tenth patient thrombosis was accompanied with cerebral coma. Urgent ultrasonography in 7 patients failed to detect a blood flow in ICA, that proved the diagnosis of ICA thrombosis; in 3 patients ultrasonography showed a mural thrombosis. Nine patients underwent reoperation in emergency, while for the tenth patient an intervention was contraindicated due to the thrombosis of middle cerebral artery, unstable clinical state (cerebral coma) and progression of neurological symptomatology. PTFE arterial graft was implantedin 7 reoperated patients with ICA thrombosis, thrombectomy from ICA was carried out in 1 patient and in another one patient a thrombectomy from reconstructed segment with PTFE patch angioplasty of the arteriotomy defect was fulfilled. In 3 reoperated patients a complete resolution of neurological symptoms was evident 24 hours after intervention, in 2 patients neurological symptomatology regressed over 2-4 weeks. In another 3 reoperated patients local neurological symptoms persisted; 1 patient demonstrated postoperative progression of neurological symptomatology and coma with fatal outcome. The last patient, for whom a reoperation was contraindicated, died due to aggravation of cerebral coma. Dynamic follow-up in early postoperative period after CEA, especially in the first 6 hours, as well as an urgent duplex scanning of the reconstructed area in case of neurological symptoms development, provides timely diagnosis of postoperative thrombosis and the success of reoperations. Adjustments to patient's cardiac status and appropriate intraoperative heparinization can decrease the risk of this complication. An urgent reoperation aimed at the restoration of carotid blood flow, immediately after the diagnosis of thrombosis (provided the absence of deep coma), promotes a complete or partial regression of neurological symptoms and helps to prevent a progression of cerebrovascular disturbances.

What influences the standards of "quality" of carotid endarterectomy?

This paper analyzes the short-term results of 463 consecutive primary reconstructive operations on the carotid bifurcation based on the standards of "quality". In 383 (82.7%) cases, the patients were operated on for stenosis of the internal carotid artery (ICA); 60 (13%) patients had combination of stenosis and kingking of the ICA and 20 (4.3%) presented with isolated kinking of the ICA. Classic open carotid endarterectomy (CEAE) was performed in 240 cases, eversion CEAE in 144, resection with ICA redressment in 45, and ICA grafting in 28 cases. The perioperative lethality accounted for 1.54% (7 cases), per 463 operations, with the standard of "quality" being equal to 2%. Myocardial infarction was the cause of death in 5 cases, one patient developed homolateral stroke which eventuated in lethal outcome, and one more patient developed lethal stroke in the contralateral hemisphere. The incidence of homolateral strokes which did not eventuate in lethal outcome accounted for 1.94% (9 cases). The indicator "stroke plus lethality from stroke" in the general patient group was 2.38% which is even lower versus the standard of "quality" for asymptomatic patients and constitutes 3%. Among asymptomatic patients proper, the indicator "stroke plus lethality from stroke" was equal to 0, among TIA patients to 0 at a 5% standard, and in patients with initial stroke, initial stroke, it amounted to 3.19% at a 7% standard. Perioperative strokes were not recorded in patients with ICA kingking or at ICA grafting. The basic factor of the risk of perioperative neurologic deficit was a history of stroke. Patients with different stages of cerebrovascular insufficiency did not significantly differ as regards age, sex distribution, the presence of CAD, arterial hypertension, diabetes mellitus, the degree of stenosis of the operated ICA and the time of its clamping at operation. Patients with a history of strokes differed significantly from the general group only in the incidence of lesion of the contralateral ICA and in the frequency of the use of internal shunt. Analysis of the risk factors of perioperative stroke in patients with a history of strokes has shown that they were diabetes mellitus and the use of internal shunt. The development of perioperative stroke among patients with a history of stroke was not influenced by the incidence of contralateral ICA lesion, the standing of cerebral circulatory distress or the size of an ischemic focus. The initial character of ICA lesion and the type of reconstruction did not affect the origin of perioperative focal deficits or lethality.

[Vasonit retard in the treatment of intermittent claudication in patients with obliterating diseases of the lower extremities]. / Vazonit retard v lechenii bol'nykh s peremezhaiushcheisia khromotoi pri obliteriruiushchikh zabolevaniiakh arterii nizhnikh konechnostei.

This paper deals with an open no incomparable study of the efficacy of vasonit retard in the treatment of intermittent claudication in patients suffering from arterial pathology. The efficacy and tolerance of vasonit retard were investigated for two months at the A.V. Vishnevsky Institute of Surgery, RAMS, and at 20 vascular departments of Russia (Moscow, Sankt-Peterburg, Nizhny Novgorod, Perm, Yaroslavl, Volgograd, Omsk, Irkutsk, Chelyabinsk, Voronezh, Rostov-on-Don, Ekaterinburg). The study accrued 25 patients treated at the A.V. Vishnevsky Institute of Surgery, RAMS, and 348 patients treated on the basis of 20 vascular departments of Russia, The basic criterion for inclusion into the study was the presence in the patient of intermittent claudication, corresponding to extremity ischemia, degree IIA end, IIB, according to the A.V.Pokrovsky classification. The treatment by vasonit retard was conducted outpatiently. The drug was administered in a daily dose of 1200 mg for 2 months. After treatment the ankle/brachial index along the posterior tibial artery and dorsalis pedis artery rose by over 17% in the group treated pt the Institute of Surgery and by over 21.5% in the group which participated in the multicenter study. The minimal pain-free distance increased by 60% and 115% respectively. The maximal pain-free distance rose by 37.7% and 98.4% respectively. A 25% abatement of the pain intensity (according to the pain score) was recorded in the group seen at the Institute of Surgery and a 36.1% pain abatement in the group included into the multicenter study. No complications leading to drug discontinuation were marked. Thus, talking into account the clinical evidence and the data supplied by instrumental diagnostic techniques, it is necessary to admit that vasonit retard is an effective drug for the treatment of patients suffering from intermittent claudication.